On this page you can read about the NERO Launch Day 27-05-2005. Although I’m couldn’t be present on the launch day (I was on a 6 month trainingship in Singapore) I translated a report which a fellow NERO member gave me.
JB wrote:
“On Friday 27-05-2005 NERO had one of it’s most beautiful launch days ever”. On that day the rockets H10a and H11d were launched.
Single stage H11d made her 4th perfect flight.
Due to the perfect weather and blue sky the entire flight could be followed by eye. On board was a R-DAS so air pressure and acceleration were measured. The payload section contained 3 gyroscopes. The military set up their actively controlled Doppler radar again so we can verify the data from the R-DAS and Gyroscopes. With the radar measurements and R-DAS data we can qualify the gyroscope set and make a reconstruction of the entire flight.
The second stage of the H10a lawn darted
The 2 stage H10a didn’t performed as well as the H11d. The rocket had a hard time leaving the launch tower and wobbled a lot during the first part of it’s flight. Separation was perfect. The ignition of the second stage was also perfect. Right on cue. Due to the wobbling the trajectory of the 2nd stage wasn’t perfectly vertical. Two people managed to track the rocket to apogee with binoculars but failed to see if the drogue deployed and lost sight afterwards. The 2nd stage lawn darted because the main wasn’t pulled out by the drogue. The drogue probably got ripped off because of due to the high horizontal velocity. The Doppler radar tracked the 2nd stage down till 800 km/h after that it lost track of it. At that moment the rocket was still accelerating at that moment. Fortunately it still landed
inside of the military premises.
At this moment the rocket still isn’t found and can take up to months to recover. The upper stage is considered to be a total loss.
Most likely situation is that the drogue got ripped of due to the high horizontal velocity at apogee. What is still unclear is why the rocket lost aerodynamic stability. This rocket passed all our stability test and the NERO actually has a lot of experience with 2 stage rocket. The H7 series had quite a number of successful flights. The instability wasn’t expected at all and further analysis will hopefully provide more data. R-DAS data is lost but we still have the data from the Doppler radar which the military provided. Last launch showed that R-DAS information and Doppler radar are within 1% of each other. So the Doppler radar can be of great help evaluating the H-10a flight.
After video analyses the most likely cause will probably be found and the lesson will be applied into the new H10b. This is the first rocket since 1996 which the NERO lost. Small mistakes causes large consequenses with AER. But as FdB put it (freely translated from Dutch): “If you can’t take it, you should start collecting stamps”.
Update 07-06-2005 2nd stage of the H-10a rocket recovered by the military
On friday morning 3th of june the military found the 2nd stage of the H-10a rocket. At first glance the electronics compartment looks ok but after inspection the following became clear:
- The back up timers had only light damage. This is actually the second time that these timers are salvaged out of a lawn dart and are still in OK condition
- The RDAS was ripped from it’s brackets and became stuck between the inner hull and the deblocking device. Parts like the micrprocessor, the flash memory, jumper, buzzer and accelerometer were ripped from the printing board. The print is damaged on one side and is beyond repair. There is good hope that he data on the flash memory can be recovered with the use of another RDAS. An attempt will be made on friday 10 th of June.
- The deblocking device fired but because there was no drogue to pull out the main it was useless. This been said it means the barometric detection of the RDAS fired the deblocking device at 200 m. So flight data up to 1 or 2 seconds before impact should be stored on the flash memory.
The place of impact was 2660 meter from the launch rail. After a quick calculation of LvV this gives an effective pitch of 50°.
